Field of the Invention
The present invention relates to a fixing apparatus provided in an electrophotographic or electrostatic image forming apparatus, such as a laser beam printer and an LED printer.
Description of the Related Art
As a fixing apparatus provided in, for example, an electrophotographic image forming apparatus, a fixing apparatus using a tubular film is proposed. Such a fixing apparatus is typically provided with a tubular film, a heater disposed in contact with an inner surface of the film, and a pressure member that forms a nip portion via the film with the heater, and heats a toner image while conveying, at the nip portion, a recording material which bears the toner image.
The fixing apparatus using the film with small heat capacity is short in warm-up time, whereas a temperature rise in a sheet non-passing portion, i.e., an excessive temperature rise in a region in which no recording material passes often occurs. Then, Japanese Patent Application Laid-open No. 11-84919 discloses a configuration in which a thermally conductive member is provided between a heater and a support member to make heat in a heater plane move easily and to make temperature distribution of the heater in the longitudinal direction uniform.
The following problem occurs, however, in the configuration in which the thermally conductive member is nipped between the heater and the support member as disclosed in Japanese Patent Application Laid-open No. 11-84919. When thermal expansion and thermal contraction of the thermally conductive member are repeated, the thermally conductive member contracts in the longitudinal direction, and an effect of controlling the temperature rise in the sheet non-passing portion may be reduced.